LED stands for a semi-conductor element, i.e., a Light Emitting Diode and is being used for an electronic screen for various electronic devices which displays various colors such as red, green, blue, yellow, etc.
An LED electronic sign board has a plurality of LEDs in a matrix which constitute pixels to display various images. Various LED electronic sign boards are installed inside or outside of the building for the advertisement or the delivery of information.
Recently, LED electronic sign board is widely being used for the display of moving image such as TV commercial as well as the display of simple texts or still images and becomes bigger, which causes the increase of electric power consumed on the LED electronic sign board. Considering that power saving technology is becoming increasingly common in the industry, it is required to reduce electric power consumed on the LED electronic sign board.